Centrifugal governor



F. HEINZMANN CENTRIFUGAL GOVERNOR Oct. 25, 1960 Filed April 6, 1956 2Sheets-Shout 1 INVENTOR. FRITZ HE/NZMANN ATTORNEYS Oct. 25, 1960 F.HEINZMANN CENTRIFUGAL GOVERNOR 2 Sheets-Sheet 2 Filed April 6, 1956 0 BM2 915551555 I INVENTOR. FRITZ HE/NZMANN 75. .0. bwffla mi g ATTORNEYSUnited States Patent CENTRIFUGAL GOVERNOR Fritz Heinzmann, Albershausen,Kreis Goppingen,

iWurttemberg, Germany Filed Apr. 6, 1956, Ser. No. 576,732

Claims priority, application Germany Apr. 9, 1955 4 Claims. (Cl. 73-537)This invention relates to new and useful improvements in centrifugalgovernors. The invention more particularly relates to a centrifugalgovernor, which allows governing over a broad range of speeds, i.e., toan all-speed governor.

Centrifugal governors having springs, which directly oppose thecentrifugal load, are known. Such governors, for example, have arotatable governor body with a pair of opposed fly weights, pivotallyconnected thereto. The governor springs, which resiliently urge the flyweights together and toward the governor body, and thus act against thecentrifugal load, are positioned about posts or spindles which extendradially from the governor body through the fly weights. The springspress on one end against the nuts or other holding members secured tothe end of the spindle, and at the other end against the fly weight, as,for example, through a pivotal knifeedge bushing.

Governors of the above construction, as contrasted with conventionalgovernors having axially arranged springs, have extremely low internalfriction, are highly sensitive and efficient, and have a long life, dueto the fact that there is no external load pressing upon the governorpivots. The centrifugal force of the fly weights is taken up directly bythe springs, so that under all operating conditions the force requiredfor control actuation by the governor, as, for example, through acontrol member, moved by the pivoting of the fly weights, is very small,as it is not necessary to counteract any spring force.

One object of this invention is a centrifugal governor of theabove-mentioned constructional type having the advantages connectedtherewith, which allows speed governing over a broad range of speed withvarying control characteristics in the different speed ranges. This andstill further objects will become apparent from the followingdescription, read in conjunction with the drawings, in which:

Fig. l is a side elevation partially in section of an embodiment of acentrifugal governor in accordance with the invention;

Fig. 2 shows the centrifugal force diagram of the governor of Fig. 1;

Figs. 3 and 4 are side elevations partially in section, showing stillfurther embodiments of centrifugal governors in accordance with theinvention;

Figs. 5 and 6 are centrifugal force diagrams of the governors of Figs. 3and 4;

Fig. 7 is a side elevation partially in section, showing still anotherembodiment of a centrifugal governor in accordance with the invention;and

Fig. 8 shows the centrifugal force diagram of the governor of Fig. 7;

Fig. 9 shows the pivotal connection between the fly weight arms 1a and1b and the control rod 14; and

Fig. shows the contact of the spring support bushing 3 with the flyweight 1.

The centrifugal governor in accordance with the invention has arotatable governor body with a pair of opposed fly weights pivotallyconnected thereto. These fly weights will pivot outwardly, due tocentrifugal force upon rotation of the governor body. Each of the flyweights has an opening defined therethrough extending in a directionsubstantially normal to the axis of rotation of the governor body. Apair of opposed spindles are radially connected to the governor body,extending through the openings in the fly weights substantially normalto the axis of rotation to the governor body. At least three separatesprings are positioned around each spindle for resiliently opposingoutward pivoting of the fly weights with at least three differentcompressive forces along the path of outward pivot thereof. Theinvention will be described in further detail with reference to theembodiments shown in the drawing.

In the embodiment as shown in Fig. 1, the governor has the fly Weights1, which are pivotally connected to the governor body 2 by means of thepivots 15. The gov: ernor body has the central portion 2a, which maybeconnected for rotation with a drive shaft. Upon such rotation the flyweights 1 will tend to pivot outwardly around the pivots 15, due to thecentrifugal force. The fly weights 1 have openings defined therethroughextending in a direction substantially normal to the axis of rotation ofthe governor body. The spindles 6 are rigidly connected to the governorbody and extend radial: ly there from through the openings in the flyweights; The axis of the spindles 6 is substantially normal to the axisof rotation of the governor body. The outward portion of the spindle isthreaded and the 'spring-retain ing nuts 12 are screwed thereon.Connected to the fly weights 1 on the other side of the pivot 15 are thearms 1a and 1b, which form an integral part of the fly weights.

The arms 1a and the control rod 14 have a slotted hole. The arms 1b havea circular hole (see Fig. 9'). These arms are pivotally connected at thepivot joint 13 to'the control rod 14 of the governor. The control rod 14is axially movable with respect to the governor body 2 and slides withinthe portion 2a of the governor body, which is rigidly screwed to themain portion 2 of the body. Upon pivoting of the fly weights outwardly,due to centrifugal force, around the pivot 15, the control rod 14 willbe axially moved, due to the connection 13 with the arms 1a. The controlrod 14 is connectedt'or control actuation in the conventional manner as,for example, to the distributor of an internal combustion engine;

The spindles 6 decrease in diameter toward their outer ends in twosteps, forming the shoulders 5 and 10. Concentrically positioned aroundeach spindle 6 is a spring support bushing 3 which has a large enoughcentral bore to fit around the shoulders 5 and 10 and which rnovablypresses against the fly weight 1. The spring support bushing 3 may haveradially extensions on each side in the form of V-shaped knife edges tofit into corresponding V-shaped grooves in the fly weights, thus formingthe contact between the fly weights and the bushings (see Fig. 10).

Additionally concentrically positioned around each spindle 6 is abushing 7 and a bushing 9. The bushing 7 has a central bore large enoughto fit around the shoulder 10 but small enough to contact the shoulder5. The bushing 9 has a central bore small enough so that the same willcontact and rest against the shoulder 10.

A first coil spring 4 is positioned between the spring support bushing 3and the bushing 9, tending to push these bushings apart. A second spring8 is positioned between the bushing 9 and the bushing 7, and a thirdspring 11 is positioned between the nut 12 and the outer side of thebushing 9.

With the governor in its rest position, the spring 11 is suflicientlytensioned, so that the bushing 9 is maintained firmly in contact withthe shoulder 10. The spring 8 maintains the bushing 7 against theshoulder 5 and the spring 4, pressing against the bushing 9, presses thespring support bushing 3 against the fly weights, maintaining the samein the pivoted position against the governor body.

As the governor starts to rotate in its low speed or first speed stage,the spring 4 is slightly pressed as the fly weights move slightlyoutwardly, moving the bushing 3 toward the bushing 9. This stage ofoperation corresponds to the portion a--b of the force diagram shown inFig. 2. Thus, at this first operating stage, the fly weights operateonly against the force of the spring 4.

After the fly weights pivot out a little further at higher speed, thespring support bushing 3 contacts the bushing 7, moving the same with itand additionally compressing the spring 8. In this connection thesprings 11 are precompressed and have sufficient tension so that thesprings 4 and 8 may be compressed there against without causing movementor compression of the spring 11. In the second stage of operation, thefly weights move against the force of the springs 4 and 8, correspondingto the portion bc shown on the force diagram of Fig. 2. The spring 11may be precompressed, so that its force just equals the combined forceof the springs 4 and 8, when the fly weights move out to suflicientpoint so that the bushing 7 contacts the bottom of the bushing 9. Uponfurther rotational speed of the governor, the fly weights will move outfurther with the force of the springs 4 and 8 remaining constant andwith the fly weights only operating against the force of the pre-loadedsprings 11. This third stage is indicated by the portion c-d in theforce diagram of Fig. 2. In the third operating stage the governor istherefore nearly astatic, the springs 11 being in a high degreeprecompressed, though during the first and second operating stages thegovernor is to a high degree static, the springs 4 and 8 being in aslight degree precompressed (see Fig. 2). This characteristic may beused for control whenever it is important to keep the regulation orspeed drop in the upper part of the speed range small, while maintainingthe regulation in the lower part of the speed range large.

The embodiment as shown in Fig. 3 is identical with that shown in Fig.1, except that the stops in the form of the annular shoulders 5 and areeliminated, and in place of the spring support bushings 9 and 7, asingle double-sided spring support in the form of the bushing 17 isprovided. This spring support surrounds the spindle 6, and since nostops are provided, the same may move axially along the length of thespindle to the spring holding means in the form of the nut 12. Thespring support in the form of the bushing 3 is identical with that shownin Fig. 1, except that the same is so dimensioned and constructed thatit will come into supporting contact and carry the double-sided support17 therewith, as the same is moved along the spindle toward the free endthereof.

A spring 16 is maintained compressed between the inner side of thedouble-sided spring support 17 and the governor body extending throughthe opening in the fly weight through which the spindle 6 extends.Another spring 4 surrounding the spindle 6 is maintained between springsupport bushing 3 and the nut 12, and a third spring 8 is co-axiallypositioned within the spring 4 surrounding the spindle 6, and maintainedbetween the nut 12 and the outer side of the double-sided spring supportbushing 17. The spring 16, which is compressed in the normal position ofthe governor with the fly weight adjacent the governor body, opposes theforce of the spring 8, and is so dimensioned and constructed that as thedouble-sided spring support 17 is moved toward the free end of thespindle 6, the same is relaxed.

In operation, as the governor body 14 is rotated in the conventionalmanner, the fly Weights pivot outwardly, due to the centrifugal force,moving the spring support bushing 3 outwardly along the spindle 6,compressing the spring 4, so that the fly Weights initially move solelyagainst the force of this spring.

When the springs support 3 contacts the double-sided spring support 17further outward movement of the fly weights I tend to compress both thespring 4 and the spring 8. The force of the spring 8, however, isinitially opposed by the force of the spring 16, pressing in theopposite direction, so that the actual force which the outwardly movingfly weights must oppose, is the force of the spring 4 and the spring 8minus the force of the spring 16. As the fly weights move further out,the spring 16 becomes relaxed, so that the fly weights must overcomeincreasing force, i.e., that the springs 4 and 8 without the aid of thespring 16. A centrifugal force diagram applicable to the governor ofFig. 3 is shown in Fig. 5. The portion cde represents the force of thespring 16, which is initially subtracted from the sum of forces of thesprings 8 and 4, represented by g-k-d-f. If the springs 16 exert asmaller force, the force diagram of the governor will correspond to thatshown in Fig. 6. Speed control with such construction is not instantlyvaried over the whole range of speeds with a neutral speed range m-nbeing inserted, whereby the governor becomes less static within thesecond stage. It is also possible to choose a third of higher speedstage ef smaller or greater in accordance with the length of the springs16.

The governor of Fig. 4 corresponds exactly to that of Fig. 3, exceptthat a stop in the form of a annular shoulder 5 is provided for thedouble-sided spring support, which is designated 18 in this embodiment.During the lower speed range of operation, the double-sided springsupport 18 is supported on the annular shoulder 5, so that the spring 16does not have to be initially compressed and need not have suflicientstrength for this function. In the construction, the beginning of thesecond or intermediate speed range is exactly fixed at the point wherethe spring support 3 lifts the support 18 from the annular shoulder 5.In all other respects the operation of the governor is identical to thatshown in Fig. 3 with in the first or low speed stage the fly weightsoperating against the force of the spring 4 alone, in the intermediatespeed or second stage the fly Weights acting against the force of thesprings 4 and 8 minus the force of the spring 16, and in the third highspeed range acting against the force of the springs 4 and 8 alone.

The embodiment shown in Fig. 7 corresponds to the previously describedembodiments except that only a single spring support, i.e., the bushing3, is provided and three springs are concentrically positioned, onewithin the other, around the spindle 6. The springs 19, 20, and 21 aresecured at their upper end to the spring-holding screws 12 by means ofpins. The inner end of the spring 19 is maintained in contact with thebushing 3 with the fly weights 1 at their normal rest position adjacentthe governor body. The spring 20 is somewhat shorter than the spring 19and at this position is spaced at some distance from the bushing 3. Thespring 21 is somewhat shorter than both the springs 19 and 20 and spacedat a still further distance from the bushing 3.

As the governor body is rotated and the fly weights move centrifugallyoutwardly, first the spring 19 is compressed, so that the fly weightsmove solely against the force of this spring. After the fly weights moveout a certain distance, the bushing 3 contacts the spring 20, so thatthe same begins to become compressed and the fly weights move againstthe combined force of the springs 19 and 20. When the fly weights moveout still further, the bushing 3 contacts the spring 21, so that the flyweights will move against the combined forces of the springs 19, 20, and21.

The force diagram 0pqr of the governor of Fig. 7 is shown in Fig. 8. Asthe elastic force curve of a cylindrical helical spring is a straightline and as the speed is a quadratic function of the elastic force andcentrifugal force, the speed curve is parabolic. Within the lowerportion of the speed range, the regulation is therefore considerablygreater than within the upper part. In accordance with the embodiment ofFig. 7, the springs 19, 20, and 21 are made effective one after theother as the fly weight moves outwardly. This produces a polygonalelastic force diagram as is required in order to obtain a low degree ofvariability of regulation. The embodiment of Fig. 7 is particularlysuitable for uses which require a low degree of variability ofregulation over the whole speed range, while not requiring thisregulation to be particularly small.

While the invention has been described in detail with reference to thespecific embodiment shown, various changes and modifications will becomeapparent to the skilled artisan which fall within the spirit of theinvention and the scope of the appended claims.

I claim:

1. In a centrifugal governor comprising a rotatable governor body, apair of opposed fly weights pivotally connected to said governor bodyfor pivoting outwardly due to centrifugal force upon rotation of saidgovernor or body, an opening defined through each of said fly weightsextending in a direction substantially normal to the axis of rotation ofthe governor body and a pair of opposed spindles connected to saidgovernor body extending through said openings substantially normal tothe axis of rotation of the governor body, the improvement whichcomprises for each spindle a first, a second, and a third spring supportsurrounding the spindle and axially movable there along, said firstspring support being axially movable along substantially the entirelength of the spindle and positioned in movable contact with the flyweight through which the spindle extends, said second spring supportbeing axially movable between substantially the outer end portion ofsaid spindle and a first stop positioned at the intermediate portion ofsaid spindle, said third spring support being positioned between saidfirst and second spring supports and axially movable along the spindlebetween substantially the outer end portion thereof and a second stoppositioned between said first stop and the inner end of the spindle,

said first spring support being dimensioned to contact said third springsupport and carry the same therewith upon axial movement along thespindle toward the free end thereof, at least one of said first andthird spring supports being dimensioned to contact said second springsupport and carry the same therewith upon axial movement along thespindle toward the free end thereof, and spring-holding means positionedat the free end portion of said spindle, a first spring mounted betweensaid first and second spring support, a second spring mounted betweensaid second and third spring supports, and a third spring mountedbetween said second spring support and said spring-holding means.

2. Centrifugal governor according to claim 1, in which said third springhas a compressive force in its normally extended position with the flyweights positioned adjacent the governor body at least substantiallyequal to the combined compressive forces of said first and secondsprings in their compressed position with said spring supports incontact with each other.

3. Centrifugal governor according to claim 2, in which said secondspring is concentrically positioned within said first spring.

4. Centrifugal governor according to claim 3, in which said stops aredefined by annular shoulders on said spindle, said second stop having alarger diameter than said first stop.

References Cited in the file of this patent UNITED STATES PATENTS654,057 Sprado Apr. 5, 1910 2,096,203 Schnurle et al. Oct. 19, 19372,139,194 Lichtenstein Dec. 6, 1938 2,631,025 Bone Mar. 10, 1953 FOREIGNPATENTS 177,055 Austria Dec. 28, 1953 843,959 Germany July 14, 1952384,976 Great Britain Jan. 12, 1933 691,011 Great Britain May 6, 1953(SEAL) UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION PatentNo. 2 957 35l October 25 1960 Fritz Heinzmann It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

In the grant line 3 for Wurttemberg" read Wiirttemberg em inthe headingto the printed specification line 3 for Goppingen read G'cippingen -==3line 4 for "Wurttemberg read Wurttemberg column 1 line 64 strike out"and"; column 2 line 53, for -"radially" read radial column 3 line 16and 17 for "springs 4 and 8' read springs 4 line 72 for body 14" read wbody 2 column 4 line 3 for "springs support read spring support line 13for "that the read that of the line 35 for "the construction" read thisconstruction column 6, line' 31 list of references cited under "UNITEDSTATES PATENTS for 654L,O5T" read 954 O5'Z e Signed and sealed this 18thday of April 1961e Attest: ERNEST w, SWIDER DAVID L D Attesting OfficerCommissioner of Patents

